Imaging of Nontraumatic Acute Hip Pain in Children: Multimodality Approach With Attention to the Reduction of Medical Radiation Exposure

Managing Pediatric Hip Pain Patients with Precision

ABSTRACT

Pediatric hip pain can have orthopedic, infectious, inflammatory, neoplastic, or nonmusculoskeletal etiologies. Organizing the differential diagnosis by symptom chronicity and a determination of intraarticular versus extraarticular pain, as well as the age at pain onset, can be helpful to hone in on the cause. Clinicians should consider plain radiographs in cases of acute trauma, with concern for bony pathology, or in patients with unexplained limp or hip pain, with musculoskeletal ultrasound and magnetic resonance imaging used as advanced imaging when indicated. Relative rest with subsequent strengthening and stretching should be prescribed in nonoperative conditions, though several pediatric hip pain diagnoses require orthopedic or other specialty referral for definitive treatment. This article is a comprehensive review of hip pain etiologies in the pediatric population.

Differential diagnosis of hip pain in children referred to a specialist bone tumour service

OBJECTIVE

To determine the differential diagnosis of bone lesions causing hip pain in children and the association between radiographic features of aggression and MRI appearances with final diagnosis.

METHODS

Retrospective review of children with hip pain referred to a specialist musculoskeletal oncology service between September 2018 and December 2020. Patient demographics, lesion location, the radiographic and MRI features, and the final diagnosis, which was made either by image-guided biopsy, surgical curettage or based on typical imaging features were recorded. Statistical analysis examined the association between the Lodwick-Madewell score (determined from available radiographs) and MRI findings with final diagnosis.

RESULTS

Fifty-nine patients were included, 40 males and 19 females with mean age 10.9 years, (range 3-16 years). Final diagnoses were based on histology in 24 (40.7%) cases and imaging in 35 (59.3%) cases. Eighteen lesions (30.5%) were classed as non-neoplastic, 31 (52.5%) as benign and 10 (16.9%) as malignant, of which four were primary bone sarcomas. There was a significant association between the Lodwick-Madewell score and final diagnosis (p < 0.001). On MRI, bone marrow oedema, presence of a focal lesion, bone expansion and the presence of an extraosseous mass were all significantly associated with final diagnostic classification.

CONCLUSION

The differential diagnosis of hip pain in children presenting to a bone tumour service is wide. Most cases are due to benign or non-neoplastic conditions, with only 10 out of 59 children having a malignant lesion. Radiography complemented by MRI plays a major role in differentiating non-neoplastic, benign neoplastic and malignant lesions and in determining the requirement for needle biopsy.

ADVANCES IN KNOWLEDGE

This is the first study to consider how imaging features relate to diagnosis in suspected paediatric hip tumours. Use of this information can help in determining which cases should undergo needle biopsy.

Pediatric Hip Disorders: Imaging Guidelines and Recommendations

Hip disorders are a wide range of conditions commonly affecting patients in the pediatric age group. Reaching an accurate diagnosis of these conditions in children may be challenging. The optimal use of image modalities in the approach of a child with possible hip pathology is essential, which allows radiologists and clinicians to narrow the differential diagnosis and reach a definitive diagnosis, which can consequently result in early and appropriate interventions leading to improved outcomes. Therefore, this article aims to provide practicing radiologists and clinicians with up-to-date and evidence-based imaging spectrum guidelines and recommendations for common pediatric hip disorders.

Yield of Plain Radiography in Addition to Ultrasound Among Children with Hip Pain

BACKGROUND

Children with limp or hip pain often undergo radiographs and ultrasound as part of their initial evaluation. Previous research suggests that hip radiography may have limited utility, and early use of ultrasound may safely reduce the use of radiographs.

OBJECTIVES

We sought to assess the utility of radiography in addition to ultrasound by evaluating the rate of bony abnormalities present on hip radiographs among children with and without effusion on ultrasound. We also assessed the agreement of point-of-care and Radiology-performed ultrasounds for the detection of effusion.

METHODS

This is a retrospective cohort study of children presenting to a pediatric emergency department with acute atraumatic limp or hip pain. Data from patients who received both hip ultrasound and hip radiography as part of their evaluation were analyzed. We included both point-of-care and Radiology-performed hip ultrasounds.

RESULTS

We identified 134 patients who received both hip ultrasound and hip radiographs. Sixty-eight patients (51%) had a hip effusion present on ultrasound and none of these had bony abnormalities on radiography (0%, 95% confidence interval 0-5.3%). Of the 66 patients (49%) who had no effusion on hip ultrasound, 2 patients were found to have a bony abnormality (3%, 95% confidence interval 0.4-10.5%). For patients who received both point-of-care and Radiology-performed ultrasound, the overall agreement for diagnosis of effusion was 92.6% (kappa = 0.82).

CONCLUSIONS

We observed that no children with an effusion on ultrasound had bony pathology on plain radiography, suggesting that the routine performance of hip radiography may not be indicated in all children. Future studies are needed to evaluate the negative predictive value of effusion in larger numbers of patients with known bony abnormalities.

Evaluation of Hip Pain and Management of Toxic Synovitis in the Ultrasound Era

ABSTRACT

The cause of acute onset hip pain in children can be difficult to determine. Once trauma is excluded, the workup revolves around determining whether there is a hip effusion and eliminating orthopedic emergencies. Point-of-care-ultrasound can be used as an adjunct in the workup. In this article, we review (1) differential diagnosis of hip pain, with a focus on toxic synovitis; (2) the evaluation of a hip for the presence of effusion, including the point-of-care ultrasound technique; and (3) the management of toxic synovitis.

Sonography of musculoskeletal infection in children

Musculoskeletal infection, especially in young children, often presents with non-specific clinical signs and symptoms necessitating early imaging to identify the source of infection. While MRI is the investigation of choice to demonstrate bone infection, it is expensive and often requires a general anaesthetic in the young child. Ultrasound can be a useful tool in the initial assessment due to its easy availability and portable equipment. It does not involve ionising radiation and is used to guide aspiration and drainage procedures. This review explains sonographic features of septic arthritis, osteomyelitis, pyomyositis and soft tissue infection in children and highlights advantages and limitations of sonography when assessing the child with suspected musculoskeletal infection.

The Diagnosis of Iliac Bone Destruction in Children: 22 Cases from Two Centres

Iliac bone destruction in children is uncommon and presents various imaging features. Correct diagnosis based on clinical and imaging features is difficult. This research aimed to retrospectively explore the clinical features, imaging, and histopathological diagnosis of children with iliac bone destruction. A total of 22 children with iliac bone destruction were enrolled in this retrospective analysis from two children's hospitals during July 2007 to April 2015. Clinical features, imaging, and histopathological findings were analysed. The mode of iliac bone destruction, lesion structure, and the relationship between the range of soft tissue mass and cortical destruction were determined based on imaging data. The data were analysed using descriptive methods. Of the iliac bone destruction cases, eight cases were neuroblastoma iliac bone metastasis, seven cases were bone eosinophilic granuloma, two cases were Ewing's sarcoma, two cases were osteomyelitis, one case was bone cyst, one case was bone fibrous dysplasia, and one case was non-Hodgkin's lymphoma. Iliac bone destruction varies widely in children. Metastatic neuroblastoma and eosinophilic granuloma are the most commonly involved childhood tumours.